1. Field of the Invention
The invention relates to a method for setting parameters of an electronically commutated motor (ECM) for use as a permanent-split capacitor (PSC) motor.
2. Description of the Related Art
As shown in FIG. 1, a typical PSC motor used as an outdoor unit of a civil HVAC system generally operates at a single rotational speed and necessitates a supply voltage of between 208 V and 230 V. The PSC motor includes a six-pole type and an eight-pole type corresponding to a high rotational speed=1075 rpm and a low rotational speed=825 rpm, respectively; besides, the PSC motor is provided with a clockwise direction CW and a counter clockwise direction CCW, thereby forming four combined states. The PSC motor has reasonable efficiency when it runs at the high rotational speed, however, the efficiency thereof is decreased to 20% below when it runs at the low rotational speed.
Most updated HVAC systems adopt an ECM motor because the power of the ECM motor is approximately proportional to the cube of the rotational speed while the power of the PSC motor is approximately proportional to the rotational speed; and when the rotational speed of the motor decreases, the power of the ECM motor is lower than the power of the PSC motor within the whole range of the rotational speed.
It is desired to develop a method for setting parameters of an ECM motor for enabling the ECM motor to substitute the six-pole or the eight-pole PSC motor directly without changing the original arrangement of wires and connection relationship of the original HVAC system, thereby realizing an advantage of the ECM motor.